Brake cylinder



Aug. 21, 19 45. s 3, W 2,383,241

' 'BRAKE CYLINDER Filed April 6. 1943 2 Shee'is-Sheet 1 NvENfoR SIDNEY 6. DOWN ATTORNEY Aug. 21, 1945. v s; DOWN 2,383,241

. ERAKE CYLINDER FildAprilB, 1943 2 Sheets-Sheet 2 INVENTOfi BIDNE Y G=- DOWN ATTdRNEY usefulness.- ot h fi us material- Patented Au 21, 1945 Westinghouse Ail-Brake Comp f Application AprilttjlilltfgjserialNo.48h995 I a r e v s-clai s rl i-r ja t x Qf. This invention relates to brahejeylinder j for ain brake equipments and more particularly to packing-means for the piston irod, infa brake c ylinder.

Thebrakecylinders, equipments are customarily mounted either on the vehicletrucksor on thevehiclebodies close to the road bed-, and consequently must be provided with means for. protecting theeop erating parts from, the dust always encounteredunder tservice conditions. Ithasalso been foundide sirablel to equip;such brake cylinders with means for lubricating the usual tubular piston rod to ininimizethe scoring ofthe surface thereof While in contact with the brake cylinderi;

epta fo m ioiib akev y s k in modern railway brake non-pressure head of the recently designed for, commercial use co'mprises an annular, packing eleinent made of felt mother n fibrous material: andmeans for subjecting the an u ar. elemento the ul f r r xe fi by the piston returnspring for wedging j the element into sealing engagement with the associated tubular piston rod, While it is desirable tgipro- I I vide resilient means to forcibly urging a pack.- ing ofg'thistype constantl into sealing engage inent withthe piston rod, the uncontrolledforce of the heavy piston; return spring in a brake compacting of th efibers and otherwise; to cause d l h age to the packing tending toshorten its lusefi ll;period,of service. Q f It is a principal object of myinventionto pro;

"Y e a mp v d. brake cylihdel packing of; the v ifect excessive to; hegannula felt. Sealin e ement; $uitab1 s.cqonera ive hthe p tonflret sprin impartin a; component. i" e Spring. force against felt elem nt. or wedein tg ain t hen st d..W 1 n ev nt neth .rej t th tion of a brake cylinder assembly embodying a packing device constructed in accordance with a d if fererit formjqf the invention; and" I 1 Fig: f1 s aigceview ofgone' of the elements 10f he-ne i d i lee n fi wli enti F u t r f lllustrated in Fi i 1' is'a brake cylinder 5: havfin'g operatively-mounted therein alpiston 6 to which isseoured a; hollow: 'piston' 'rod 1 ,the outer endof" which extends through an opening 8 formedina non-pressure=head-:9l A coil return spring- I0- ls provided for biasingthe piston 6 toward brakerelea'seposition; one end of the spring being mounted in engagement with the piston and the other-tend 'beihgadaptedto seat posed withinythe non-pressureheadt;

- According to the inventiomwthe piston rod packing assembly N 5 comprises; an annular filter and lnbricaton nieinberlflwi which; may be made oi fel tor ether 'flbreus materlal; and' a plurality of separate-spring seat members 14; which :are

substantially arcuate in formv and are: assembled in end -to-end relationship between the adjacent endef the -coilr spring 1 0 and the annular member l3; The innen-surface-of'the fibrous packin member I S' is adapte'd to be main-tained' in sliding gement with the hollow: piston Iqdl Liand maybe suita-bly; treatedwith lubricant ifvdesired. i

AS'ShOWI'I inFigLlgithetfibr ousrpacking mem be-r l l3tof the assembly is constantly wedged-jtoward the hollow piston area: 1' by; reason. ofthe fact-that the outer portiongofathe annular pack ing. element; is.interposdqrbetween oppositely slanting. surfaceslof the non-pressure heade and of the several spring seat members I4, against 'which the 'coil springs-I0 exerts a'r nthrust'."

1 Each of the spring'seat members Mhas formedon thejarcuatebody thereof an outwardly ex- 'tending 'footrportion l1; which isengageable with the en'd wall ofi the nonvpressure headat 1 It will be-observedthat. the medial? portion of: each seat r :member: l4 istcahted, to provide awedging surface cooperable with .the fibrous element; I3; :and r alsorto" provide-asuitab1e tofh set surface adapted to fit into the endof thecoil spring lfl when theparts are assembled. With the elements assembled as shown in Fig. 1, the spring seat members M are adapted to divide the total thrust of the release spring l0, one component of the force being directed harmlessly against the non-pressure head 9, while another component is applied to the fibrous packing member l3.

Excessive crushing or distortion of the soft pack,-

ing member [3 is thus avoided, although the" t i l wedging force exerted thereon by the release spring I is sufiicient to maintain the desired sealing contact of the packing member with the hollow piston rod 1.

Embodiment in Figure 3 an opening 2| through which extends the usual tubular piston rod 22. It will be understood that :1 1. In a brake cylinder having a non-pressure the piston rod 22 is connected to a piston, ;not

shown in Fig. 3, the piston being urged toward normal or release position by theforce exerted by acoil spring 23 encircling thepi'ston ro The piston rod packing assembly embodying the form of the invention disclosed in Fig. 3 includes an annular channel or jacket member, preferably made of metal such as spring steel; and interposed between the end wall of the nonpressure head ZO an d the piston return spring 23, and an annular filtering. and lubricating element 25, which is made of soft fibrous material such as felt, and which has an inner surface adapted to fit snugly about the piston rod 22.

The annular. jacket member is substantially -U-shaped in .cross section, and constructed and arranged to have suflicient rigidity to withstand the force exerted by the release spring 23-when the several. elements are assembled as shown in Fig. 3. An annular depression 21 is formed on the inner skirt of the jacket member 24, the

depression having a diameter approximately equaling that, of the coilspring 23. Both skirts of the jacket member are inclined, as shown in Fig. 3, so'that the fibrous element 25 confined between the skirt portions is subjected to a wedgin'g" force tending to maintainv contact between .thatelement and the hollow piston rod 22, resulting from limited flexure of'the springsteel jacket member under .the thrust of the spring 23. As

I is best shown in Fig. 4 of the drawingsa plurality of radially disposed slots 29 are preferably.

formed in the skirt of the annular jacket member' 24 against which the spring 23 is adapted .to seatp'to permit the limited flexing just described. These slots terminate outwardly of the annular'depression 21 so that thelowermost portion of the jacket member may serve to containa quantity of lubricant, indicated by the reference character 30 in Fig. 3. The annular fibrous element '25 is thereby maintained in a condition to provide sufiicient. lubrication of the hollow piston rod 22 over-a relatively long period of time:-

It will'thus be'understood that the annular jacket member 24, in combination with the felt orfibrous packing element 25 mounted therein, will serve to support the adjacent end of the coil release spring 23 in proper alignment with respect'to the other elements of the brake cylinder assembly, and that with the jacket member so constructed as to permit slight yielding of the skirt thereof containing. the radial slots hereinbefore described, the component forces exerted by the coilspring 23 will be distributed partly through the medium of the fibrous packing elehead, a piston rod extending through an opening therein, and a piston return spring coiled coaxially'about said rod, the combination therewith of a piston rod packing assembly comprising an annular channel member interposed between "said spring and an end wall of said non-pressure head and encircling said piston rod, and'an annular fibrous packing element mounted within .said channel element and having an inner surface disposed in sealing engagement with said piston rod, said channel member having a skirt portion which is yieldable so as to transmita component of the total force exerted -by said spring t0 said fibrous packing element-for urging same against thepiston rod.

2. In a brake cylinder having anon-pressure head, a piston rod extending through an opening therein, and a piston return spring coiled about I said rod} in combinati0n", an annular fchannel element formed of substantially rigid material and adapted to be'interposed between said'spring and said non-pressure .head; said channel element having one wall thereof formed with an annular recess for receiving the end of said spring and a plurality of radial slots =for rendering'a portion of said wall relatively yieldable, vand an annular packing member formed of fibrous material clamped within said channel element, said fibrous packing member being subject to the wedging action of said flexible wall of .the channel element resulting lfrom the thrust of said S ng.

3. In a brake cylinder having. anon-pressure head a piston rod extending through an opening therein, and a piston return spring coiled coaxially, about said rod, the combination therevwith of a piston rod packingassemblageinterposed between said spring and said nonepressure head andcomprising an, annular jacket member substantially U-shaped in. cross section and. havingone skirt portion for engaging the. non-.pre'ssure head and another skirtpor-tion which is indented forseating said spring,,said other skirt portion being slightly yieldable to .Yth'e pressure .of said spring, and. an annular packing member formed of lubricant absorbing material mounted between the skirt portions of said jacket member, said packing member being of smaller diameter than said jacket member to thereby provide within the jacket member an annular chamber surrounding said packing member for containing a quantity of lubricant for said packing member.-

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